Device for projecting drawings



March 16, 1954 H. E. POL'LITT 2,671,965

DEVICE FOR PROJECTING DRAWINGS 2 Sheets-Sheet 1 Filed June 27, 1952 I INVENTOR HAROLD E. POLLITT 24 r- ATTORNEYS March 16, 1954 H. E. POLLITT 2,671,965

DEVICE FOR PROJECTING DRAWINGS Filed June 27, 1952 2 Sheets-Sheet 2 W 5154; Mmfi B "Tmzmfv' ATTORNEYS Patented Mar. 16, 1954 UNITED STATES FATENT OFFICE DEVICE FOR PROJECTING DRAWINGS Harold E; Pollitt, Dayton, Ohio Application June 27, 1952, Serial No. 295,919

8 Claims.

This invention relates to a drafting machine particularly a machine for converting rectilinear two-dimensional views such as plan views and elevations into perspective views.

In the drafting art, a perspective view is many times required or desirable in order to give a proper illustration for quick and ready understanding or for the purpose of showing in one 'view a more complete structure than can possibly be illustrated in conventional views such as plan views and elevations.

The drawing of perspective views is quite difiicult and time-consuming and a great many draftsmen and illustrators who have adequate skill in rendering two-dimensional views do not have the ability to draw proper perspective views.

Furthermore, the drawing of such views is laborious and time-consuming, particularly where it is desired for the illustration to correspond closely with the actual subject.

Having the foregoing in mind, it is a primary object of the present invention to provide a device whereby perspective views can readily be drawn from plan and elevational views and without any laborious and time-consuming layouts and measuring being required.

It is another object to provide a device of the nature described which can readily be placed in position on a drawing board or drawing table for use and readily detached therefrom.

A still further object is the provision of a drafting device of the nature described which is small and can, therefore, readily be stored when not in use.

A'still further object of this invention is the provision of an instrument of the nature described, which is readily adjustable, whereby it becomes highly flexible so as to be usable under substantially all circumstances arising in the art of drawing perspective illustrations.

These and other objects and advantages will become more apparent upon reference to the following specification taken in connection with the accompanying drawings in which:

Figure 1 is a plan view showing a substantially conventional drafting board or drafting table having mounted thereon the device of the pres ent invention;

Figure 5 is a plan view of the device showing two adjustments for reproducing a plan view at one perspective angle;

Figure 6 is a view like Figure 5 but showing the device adjusted for drawing an ellipse;

Figure 7 is a sectional perspective view showing a pivot forming a part of the device and is indicated by line ll on Figure 6;

Figure 8 is a sectional view indicated by line 8--8 on Figure 6 showing a slidable connection between two parts of the device;

Figure 9 is a sectional perspective view'indicated by line 9-9 on Figure 5 showing the tracing point of device;

Figure 10 is a sectional view indicated by line Hll6 on Figure 6 showing the construction of an adjustable pivot forming a part of the device; and

Figure 11 is a sectional view taken on line I l-I I of Figure 6 showing the pivot for a portion of the device.

Referring to the drawings somewhat more in detail, in Figure 1 there is illustrated a substantially conventional drafting board or drafting table In, having a conventional drafting machine [2 mounted thereon that comprises the two straight edges [4 and |6.' Adapted for mounting on one of the said straight edges is the device according to my invention, generally indicated at I8.

The device is more fully illustrated on Figures 2 through 10 wherein it will be seen to comprise a base member 26 adapted for being secured to one of the arms I4, [6, of the drafting machine referred to above, or for being held stationary by means of feet 24 which may advantageously be formed of rubber. The clip 22, of conventional design, can be employed to secure the device to a straight edge.

Base member 20 has slidably mounted thereon a plate or panel 26. As will be seen in Figures 6 and 8, base member 20 may comprise anti-friction means 23 slidably supporting panel or plate 26. for movement thereon while rollers 30, carried along the side edges of base member 20, engage the adjacent, side edges of panel or plate 26 and thereby guide the panel on the base member for true rectilinear movement relative thereto. Advantageously, rollers 36 may be grooved for'receiving a tenon on the edge of plate 26 whereby the engagement of the rollers with the plate also retains the plate in assembled relation with the base.

At the left side of plate or panel 26 there is a fixed pivot 30, illustrated in detail in Figure"! and which slidably receives a bar 32 by means that they will always move together.

3 of the slot 34 in the said bar. Bar 32 thus always pivots about the axis of pivot 30 but is slidable on the pivot in the direction of the length of the bar.

At its end opposite its connection with pivot 33, bar 32 has pivoted thereto a small holder 36 adapted for carrying the pencil or pen scriber 33. A finger lever 40 may be provided for tipping holder 36' upwardly about pivot 42 to lift the scribing point from the paper and may be adapted to hold the scriber upward for movement to another position. At the pivot 42 a cam portion 31 is provided on holder 36 and a spring 39 cooperates therewith for holding the holder in its raised and lowered positions.

Also adjacent the end of bar 32 that carries the scribing point, there is pivoted to the arm by means of pivot pin 44, a block 46. Block 46 slidably fits in a slot 48 in the plate or member 50 that is pivoted at 52 to panel 26. The opposite: ends of plate 50 are provided with arrow points for registration with the scale 54 and it will be evident that plate 50 can be adjusted precisely on panel 26 to any predetermined angle and locked in that position.

Figure 11 will serve to reveal that pivot 52 for plate 50 is formedby a screw extending through a bore in panel 26 having a nut in a counterbore on the bottom side of panel 26 and a head in a counterbore on the upper side of panel 26 that is welded to plate 50.

At the right side of panel 26 there is formed a slot 56 which receives a member 53 that is adapted for being fixedly clamped in any predetermined position of adjustment along slot 56 by means of the clamping screw and wing nut arrangement 60, best seen in Figure 10.

Member 58 comprises a laterally projecting portion 62 terminating in a point adapted for registration with a scale 64 on panel 25. Adjacent the point end of portion 62 is a pivot 66 corresponding in construction with pivot 36 in that it provides a pivot axis for a bar 66 that has a slot ll slidably engaging the said pivot. Bar 68, similarly to bar 32, will always pivot about pivot 66 but is slidable in the direction of its length thereon.

At its end opposite its engagement with pivot 66, bar 68 is connected by a pivot pin with a block 12 that is slidably mounted in a slot or guide 14 that extends transversely in panel 26. Beyond pivot pin 10, bar 63 is adapted for mounting a tracing element 16 by means of which the lines of a drawing to be reproduced can be f0llowed. Tracing element 16 may advantageously be mounted on the end of arm 68 by a pivot corresponding to the pivotal connection of the scribing point with its arm 32.

A link 18 extends between pivot pins 44 and I0 and thus interconnects arms 32 and 68 so Due to the fact that pivot 66 is adjustable and the fact the angularity of slot 48 can be changed, however, the movement of arm 32 in response to movements of arm 63 does not always cause scribing point 38 to follow the same path as tracing point 16, as will be seen hereafter.

The base member as may be provided with a hand bar 80 if desired, secured thereto by screws 82 to facilitate moving of the device.

For the purpose of causing tracing point it to move in a circular path, there may be provided for detachable connection to base member 253, a device indicated at 84 and which consists of a rigid bottom part 86 having a pivot 88 that adjustably receives a slotted bar 90. The construction of pivot 88 is illustrated in Figure 4 and it will be appreciated that bar 90 can be adjusted on the pivot in the direction of its length by availing of the wing nut 92 and, when the bar 90 is clamped in fixed position on the pivot, it will be free to rotate thereabout. At its end opposite its connection with pivot 88, bar 98 includes a sleeve 94 for receiving tracing point i6. A scale 96 serves to indicate the radial distance from the axis of pivot 88 to the axis of sleeve 94, thereby to indicate the radius of the circle about which the tracing point will turn when the described adjustment is in place.

Turning now to Figure 5, there is illustrated therein the manner in which the device of the present invention is adjusted for converting plan or elevational view I00 into a perspective view I02. In accomplishing this, the member 58 at right side of panel 2% is adjusted in its slot until it registers with the indication on scale 64 representing the incident angle between the line of sight and the subject as it is to appear in the perspective view E02. Also, plate 59 is adjusted on its pivot 52 until it registers with the proper indication at the proper point along scales 54. The device is then adjusted with tracer point 16 located at some predetermined point about drawing H38. Thereafter, when tracer point 16 is moved tofollow the outline of the drawing, scribing point 38 will draw out view I62. The angularity of view 562 will be determined by the setting of the plate 56 and the foreshortening of the angular lines of the view will be determined by the setting of member 58. Vertical movements of tracing point 16 will appear as equal vertical movements of scribing point 38 because when tracing these lines, arms 32 and 68 move as a single unit together with panel 26.

When circles are to be reproduced, plate 50 is adjusted as illustrated in Figure 6- either to a horizontal position or to such angularity as is required in order to provide for the proper angle for the major axis of the ellipse to be drawn while member 58 is adjusted in its slot to the proper position along scale 64 to provide for the proper ratio between the major axis and the minor axis of the ellipse to be drawn. In reproducing a circle, tracing point 16 can either trace the circle itself, or can be guided in a circular path by the attachment 84 previously described.

From the foregoing, it will be seen that what my invention provides is an extremely simple, compact device for the purpose of transforming plan and elevational views into perspectives, quickly, simply, and without any particular skill being required.

It will b understood, of course, that in drawing a perspective view showing, for example, the front and right side of a subject, first the front elevation of the subject would be converted into a perspective showing thereof, and then the right side elevation would be drawn in at the proper angle connecting thereto and then the top of the view, either filled in from the perspective illustrations already drawn, or supplied from a top plan view. In this manner, perspective views of any size can be built up and a wide variety of illustrations can be provided for.

It will be understood that this invention is susceptible to modification in order to adapt it to different usages and customs, and it is accordingly desiredto comprehend such modification as may be considered to comewithin the scope of the appended claims.-

first and second arms respectively slidably engaging said pivots and extending therefrom in the same general direction to beyond one edge of said panel, said first arm having a tracing point on its projecting end and said second arm having a scribing point on its projecting end, a guide adjacent the said one edge of said panel extending laterally therein and means on said first arm engaging said guide, means forming a guide adjacent the said one edge of the panel in the region of the second arm, means on the second arm engaging the second guide, said second guide being adapted for guiding the adjacent point of the said second arm in a straight line and being angularly adjustable on said panel, and means comprising a link interconnecting said arms in the region of the guided portions thereof for simultaneous swinging movements of said arms about their respective pivots.

2. In a drafting device of the nature described: a pair of laterally spaced arms extending in substantially the same direction, a panel beneath said arms, and beyond one edge of which the arms extend, a transversely extending guide on the panel adjacent the said one edge in the region of one of the arms, a member slidably fitting said guide and connected with said one arm, an angularly adjustable straight line guide adjacent the said one edge of th panel in the region of the other arm, a member on said other arm slidably engaging said angularly adjustable guide, pivots for said arms on said panel spaced from said guides and each said arm slidably engaging its respective pivot, a link connecting said arms in the region of the connection of said arms with said members, a tracing point on the projecting end of one of said arms, and a scribing point carried by the corresponding end of the other said arm. f

3. In a drafting device of the nature described: a panel guided for rectilinear movement in one direction, a guide slot extending transversely to said direction at one side of said panel, a second guide slot in substantially the same transverse plane at the other side of the panel and said sec ond guide slot being angularly adjustable on the panel, a first arm having means engaging said first guide slot, a second arm having means engaging said second guide slot, a pivot on the panel for each said arm, each said arm slidably engaging its respective pivot, means adjustably supporting the pivot for the said first arm for movement of said pivot toward and away from said first guide slot, a tracing point on the end of one said arm, and a scribing point on the end of th other said arm.

4. In a drafting device of the nature described: a base member, a panel on said base member guided thereon for rectilinear movement in one direction at right angles to one edge of the panel, a pair of arms on the panel extending beyond the said one edge thereof, and laterally spaced in the direction of the said edge, a transverse guide slot formed in said panel adjacent the one edge, under one of said arms and means on the said one arm engaging said slot, means under the other arm adjacent the said one edge or the panel forming a straight line guide slot and means on the said other arm slidably engaging that said slot, the said means forming the second slot being angularly adjustable on the panel, a stationary pivot for said other arm on said panel,

a pivot for said one arm adjustable on said panel toward and away from the first-mentioned guide slot, said arms slidably engaging their respective pivots, a tracing point on the end of said one arm, and a scribing point on the end of said other arm.

I Y 5. In a drafting device of the nature described:

a base member, a panel on said base member guided thereon for rectilinear movement in one direction at right angles to one edge of the panel, a pair of arms on the panel extending beyond the said one edge thereof, and laterally spaced in the direction of the said edge, a transverse guide slot formed in said panel adjacent the one edge, under one of said arms, and means on the said one arm engaging said slot, means under the other arm adjacent the said one edge of the panel forming a straight lineguide slot .and means on said other arm slidably engaging the second of said slots, the said means forming the second or said slots being angularly adjustable on the panel, a stationary pivot 'for said other arm on said panel, a pivot for said one arm adjustable on said panel toward and away from the firstmentioned guide slot, said arms slidably engaging their respective pivots, a tracing point on the end or said one arm, and a scribing point on the end of said other arm, said base comprising detachable means including a rotatable arm adjustable in length, adapted for engagement with said tracing point for guiding said tracing point in a circular path.

6. In a drafting device of the nature described: a base member, a panel on said base member, guided thereon for rectilinear movement in one direction at right angles to one edge of the panel, a pair of arms on the panel extending beyond the said one edge thereof, and laterally spaced in the direction of the said edge, a transverse guide slot formed in said panel adjacent the one edge under one of said arms, and means on the said one arm engaging said slot, means under the other arm adjacent the said one edge of the panel forming a straight line guide slot and means on the said other arm slidably engaging the second said slot, the said means forming the second said slot being angularly adjustable on the panel, a stationary pivot for said other arm on said panel, a pivot for said one arm adjustable on said panel toward and away from said first-mentioned guide slot, said arms slidably engaging their respective pivots, a tracing point on the end of said one arm, and a scribing point on the end of said other arm, said base being adapted for being connected with one of the arms of a conventional drafting machine.

7. In a drafting device of the nature described: a base member having upwardly projecting flanges at its side edges, a panel mounted on said base member between the flanges, roller means positioned between the side edges of panel and said flanges for guiding the panel on the base member in rectilinear movement, a pair of arms in laterally spaced relation on said panel, one point on one arm being guided on said panel for movement in a direction at right angles to the direction of movement of the panel on the base, a corresponding point on the second arm being guided for straight line movement on the said panel, at any predetermined angle to the said direction of rectilinear movement, a rigid link connecting the said points on said arms, a pivot for each arm on the panel spaced from the said guide point of the pertaining arm, each arm slidably engaging its respective pivot, a tracing point memes on the. end of the said one arm on the omreait side, of the. guide poi-ntthereof, from the Billet pertaining thereto, and, a tracin point on the correspond-me end of the second arm.

a. In a drafting device, of the nature described: a base member having upwardly projeeting flanges at its side edges, a panel mounted on said base member between the. flanges roller means positioned between. the side edges of. panel and under said flanges for guiding the panelon the base member in rectilinear movement, a pair of arms in laterally spaced relation on said panel, one point on one arm being guided on said panel for movement in, a, direction at; right angles to the direction of, movement of the panel on the ba a corr sp ding point on the second arm beingv guided for straight line movement on the said panel, at any predetermined an le to the said direction of rectilinear movement, a rigid linkconnecting the said points on said arms, a pivot for each arm, on, the panel spaced from the said guide point of the pertaining arm, each arm slidably engaging its respective pivot, a; tracing paint on. the. end of the aid; one, arm on t e pposite; side of: the: gu de poi t thereof train the pivot pert i ing thereto. a d a traeine: neint on the correspondin end of the second arm th pivot:v for said onewarmbeing; j-us ab y s cured to saidnan l for adjustment thereo and in a direction, parallel, tov the direction of said rectilinear movement.

HAROLD PQLLITI.

References Cited in the file of this patent UNITED STATES PATENTS Number Nam Date 51.2,, Kl ri i ,1-."-s Jan- .5 L8 1,408,045 Tiffany .1 Feb. 23, 19.22

FOREIGN PATENTS Number Country Date 29,002 Germany Oct. 8 1884 83,869 Austria May 10., 19,21 

